Pivotable clamping electrical heating device for a thermoplastic pipe welding jig

Abstract

A heating device for a welding jig having two guide arms for welding together plastic pipe comprises two semi-circular electrical heating plates joined at one end by a pivotal or adjustable connection. Both ends of the heating plates have recesses for receiving the two guide arms when the heating device is in its closed position, enclosing the plastic pipes to be welded. The non-pivotally or non-adjustably connected ends of the heating plates are held together by a quick-release closure, such as a toggle catch, when the heating device is in its closed position.

We claim: 
     
       1. In a heating device for a welding jig having two guide arms with clamping devices for securing in place one of plastic pipe sections and plastic moldings to be welded together, said clamping devices being displaceable in relation to each other, and having two semi-circular electrical heating plates with facing interior receptacles and free ends which are connectable to each other, the improvement comprising: a receptacle radius of the facing interior receptacles (14, 24) of the semi-circular electrical heating plates (11, 21) being one of equal to and greater than an inner pipe radius of an outer inner pipe circumference of an inner pipe (40) on which an outer pipe (41) to be welded is slipped,   a plate radius of an outer plate circumference (15, 25) of the semi-circular electrical heating plates (11, 21) being greater than an outer pipe radius of an outer pipe circumference of the outer pipe (41),   the semi-circular electrical heating plates (11, 21) having radially outwardly directed extensions (12, 16, 22, 26) on said free ends, said radially outwardly directed extensions having, on extension sides facing each other, recesses (13, 17, 23, 27) to receive the guide arms (45, 46) of the welding jig,   the semi-circular electrical heating plates (11, 21) having connecting points disposed in the radially outwardly directed extensions (12, 16, 22, 26) outside of said recesses (13, 17, 23, 27) for the guide arms (45, 46),   a recess distance between the centers of the recesses corresponding to a guide arm distance between the center longitudinal axes of the guide arms, and   a plate distance between the receptacle center of the receptacle formed by the semi-circular electrical heating plates and the centers of the recesses corresponding to one half said recess distance.   
     
     
       2. A heating device in accordance with claim 1, wherein one half of each of the recesses (13, 17, 23, 27) is located on each of the two semi-circular electrical heating plates (11, 21).   
     
     
       3. A heating device in accordance with claim 2, wherein the semi-circular electrical heating plates (11, 21) are pivotally connected at a corresponding first set of said radially outwardly directed extensions (12, 22), a pivotal axis of pivot (20) being oriented parallel to heating surfaces of the semi-circular electrical heating plates (11, 21).   
     
     
       4. A heating device in accordance with claim 2, wherein the semi-circular electrical heating plates (11, 21) are adjustably connected to each other at a corresponding first set of said radially outwardly directed extensions (12, 22), a direction of adjustment being oriented perpendicular to a plane of separation of the semi-circular electrical heating plates (11, 21).   
     
     
       5. A heating device in accordance with claim 4, wherein a corresponding second set of said radially outwardly directed extensions (16, 26) of the semi-circular electrical heating plates (11, 21) are securable to each other by a quick-release closure.   
     
     
       6. A heating device in accordance with claim 5, wherein each of the recesses (13, 23) in said corresponding first set of said radially outwardly directed extensions (12, 22) are in a shape of one of semi-circular and rectangular grooves adapted to fit around one-half of each of the guide arms (45, 46).   
     
     
       7. A heating device in accordance with claim 6, wherein each of the recesses (17, 27) in said corresponding second set of said radially outwardly directed extensions (16, 26) are open towards an end of the radially outwardly directed extensions (16, 26) and have a depth of a radius of the guide arms (45, 46).   
     
     
       8. A heating device in accordance with claim 1, wherein the semi-circular electrical heating plates (11, 21) are pivotally connected at a corresponding first set of said radially outwardly directed extensions (12, 22), a pivotal axis of pivot (20) being oriented parallel to heating surfaces of the semi-circular electrical heating plates (11, 21).   
     
     
       9. A heating device in accordance with claim 1, wherein the semi-circular electrical heating plates (11, 21) are adjustably connected to each other at a corresponding first set of said radially outwardly directed extensions (12, 22), a direction of adjustment being oriented perpendicular to a plane of separation of the semi-circular electrical heating plates (11, 21).   
     
     
       10. A heating device in accordance with claim 3, wherein a corresponding second set of said radially outwardly directed extensions (16, 26) of the semi-circular electrical heating plates (11, 21) are securable to each other by a quick-release closure.   
     
     
       11. A heating device in accordance with claim 8, wherein a corresponding second set of said radially outwardly directed extensions (16, 26) of the semi-circular electrical heating plates (11, 21) are securable to each other by a quick-release closure.   
     
     
       12. A heating device in accordance with claim 3, wherein each of the recesses (13, 23) in said corresponding first set of said radially outwardly directed extensions (12, 22) are in a shape of one of semi-circular and rectangular grooves adapted to fit around one-half of each of the guide arms (45, 46).   
     
     
       13. A heating device in accordance with claim 8, wherein each of the recesses (13, 23) in said corresponding first set of said radially outwardly directed extensions (12, 22) are in a shape of one of semi-circular and rectangular grooves adapted to fit around one-half of each of the guide arms (45, 46).   
     
     
       14. A heating device in accordance with claim 3, wherein each of the recesses (17, 27) in said corresponding second set of said radially outwardly directed extensions (16, 26) are open towards an end of the radially outwardly directed extensions and have a depth of a radius of the guide arms (45, 46).   
     
     
       15. A heating device in accordance with claim 8, wherein each of the recesses (17, 27) in said corresponding second set of extensions (16, 26) are open towards an end of the radially outwardly directed extensions (16, 26) and have a depth of a radius of the guide arms (45, 46).   
     
     
       16. A heating device in accordance with claim 9, wherein a corresponding second set of said radially outwardly directed extensions (16, 26) of the electrical heating plate (11, 21) are securable to each other by a quick-release closure.   
     
     
       17. A heating device in accordance with claim 9, wherein each of the recesses (13, 23) in said corresponding first set of said radially outwardly directed extensions (12, 22) are in a shape of one of semi-circular and rectangular grooves adapted to fit around one-half of each of the guide arms (45, 46).   
     
     
       18. A heating device in accordance with claim 9, wherein each of the recesses (17, 27) in a corresponding second set of said radially outwardly directed extensions (16, 26) are open towards an end of the radially outwardly directed extensions (16, 26) and have a depth of a radius of the guide arms (45, 46).